Background & Management



Displacement of proximal femoral epiphysis in the immature hip

- due to imbalance of mechanical and endocrine factors 




Age Peak Incidence : M 12-14; F 11-13; Slight downward trend due to earlier maturation of children

L hip > R

10 / 100 000


Bilateral SUFE


No endocrine abnormality

- 20% at time of of diagnosis

- another 20% during diagnosis

- up to 60% with long term follow up


Endocrine abnormality

- up to 75%


Risk Factors


Demographic Factors

- Increased Weight and Height (50% over 95th percentile weight; 50% over 97th percentile height); Average BMI 27  

- Race : Increased risk in Black pts (4X) ; Polynesian ; Hispanics

- Sex : Male 2.5 x risk

- Family History - 7 % risk to other family members


Hip Mechanical Factors - increased shear forces

- increased slope (at adolescence growth plate goes from horizontal to vertical position)

- increased retroversion Southwick angle > 14

- reduced neck shaft angle



Imbalance of

- Testosterone - causes physeal fusion

- Growth hormone - causes physeal hypertrophy / weakens



- hypothyroidism

- hypopituitary

- acromegaly or growth hormone supplementation

- CRF/ Renal Osteodystrophy



Connective Tissue Disorders - Marfan's / Downs / Ehlos Danlos

Chemo therapy / DXRT




Widened hypertrophic zone 

- constitutes 60% of physeal width 


Abnormality at Hypertrophic & Proliferative Zones junction

- failure occurs here

- disordered chondrocyte columns

- decreased number of cells

- cells smaller

- increased number of dead and degenerative cells


Head remains in acetabulum via L. Teres

- neck displaces anterosuperior on physis and ER

- head slips posterior / inferior on neck






Acute < 3/52 symptoms

Acute on Chronic 

Chronic >3/52




Southwick Slip angle

- Wayne Southwick ; 1st Chairmen of Orthopaedics at Yale University

- lateral X-ray  / frogs legs

- epiphyseal-shaft angle 

- angle of interest is the angle of the affected side subtracted from the normal contralateral side ; if contralateral SUFE then 12 degres as normal    

- <30° / 30- 50 / >50°

- mild / moderate / severe




Loder JBJS 1993



- able to weight bear / 0% AVN



- unable to weight bear / AVN rates 10 - 60%




Overweight adolescent boy hip or knee pain; 30% present only with knee pain





Walk with ER (chronic) i.e increase in foot progression angle

Obligate abduction and external rotation with flexion

Limitation IR / Abduction

LLD (real and apparent)








Trethowan Line / Kleins Line

- line along superior neck usually transects 20% head

- originally described as AP but can also be used as lateral


Widened physis


Inferomedial remodelling in chronic slip


Metaphyseal Blanch Sign of Steel

- Increased cresenteric density in the metaphysis due to overlapping of the metaphysis with the epiphysis


Capener's Sign

- the posterior acetabular margin normally cuts the medial corner of the metaphysis

- in a slip the whole of the metaphysis remains lateral to the acetabular margin


Frog Leg Laterals / Shoot through lateral


SUFE Lateral


Shoot through lateral

- best to avoid frog leg lateral as may displace slip


Posteriorly displaced & angulated


Measure Southwick Angle

- calculate severity of slip

- also estimates risk of slip of other side / looking for retroversion






1.  Prevent further slip / obtain physis fusion

- 30% will continue untreated


2   Prevent deformity and OA

- MUA / ORIF / osteotomy


3.  Avoid complications 




Loder RT et al. What is the best evidence for treatment of slipped capital femoral epiphysis?

Journal of Pediatric Orthopaedics. 2012 Sept : 32 (Suppl 2) S158 - 65


Stable : Insitu Pinning current gold standard


Unstable : Two schools of thought

  1) < 24 hours old

- Consider treatment as a surgical emergency

- urgent reduction (gentle traction, flexion and internal rotation) +/- joint decompression

- probably results in lowest AVN rates (Petersen et al - refer below)

- alternatively consider discussion with tertiary paediatric referral centre


  2) > 24 hours

- Discuss with specialist paediatric centres

- possibility of surgical dislocation and realignment i.e. Modified Dunn Procedure


In Situ Pinning


Gold Standard (Techique refer below)


CT post operatively

- ensure no screw protrusion


TWB 6/52


Serial Xray

- ensure epiphysis doesn't grow off screw

- screw can break / can lose position

- observe til physis closes

- no indication to remove pin




Weinstein et al JBJS Am 1991

- 40 year follow up of 155 hips

- some pinned in situ / some realigned / some reduced

- rates of OA / AVN / chondrolysis increased with severity of slip

- rates of OA / AVN / chondrolysis increased with reduction / realigned

- regardless of severity of slip, pinning in situ had best results with lowest complications


Closed Reduction Prior to Pinning




Traditionally associated with higher risk AVN





- may decrease AVN in severe, unstable hips

- prevent severe deformity / late OA




Acute & unstable < 24 hours




Peterson et al J Paediatr Orthop 1997

- 91 cases of severe, acute, unstable slips

- 42 closed reduction < 24hrs AVN 7%

- 49 closed reduction > 24hrs AVN 20%

- hypothesised that had acute obstruction of epiphyseal vessels 

- timely decompression allows revascularisation

- treat an acute unstable slip as per a fracture

- these have up to 50% AVN rate anyway

- emergency operation


Chen et al J Paediatr Orthop 2009

- 30 acute, unstable slips

- 25 closed reductions and 5 open reductions with release hematoma

- 4 cases of AVN


Open Reduction Prior to Pinning



- severely displaced slips



- moderate or severe slips do poorly in long term

- best treatment is intra-capsular reduction or osteotomy

- risk AVN either way

- acute open reduction easier

- also decompress hip


Modified Dunn Procedure


Ziebarth et al. Capital realignment for moderate and severe SCFE using a modified dunn approach.

Clin Orthop Relat Res. 2009; 467(3): 704 - 16

- Ganz type transtrochanteric approach

- Z shaped capsulotomy to preserve superior vessel along neck, along anterior acetabulum and inferior neck

- capsule banana skinned off neck

- hip dislocated via adduction and external rotation and transection of the round ligament

- epiphysis taken off neck, still attached to capsule

- intraoperative monitoring of epiphyseal perfusion via 2mm hole drilled in the anterior neck or via insertion of ICP monitor into the epiphysis

- neck debrided to avoid tensioning of posterior vessels

- head replaced and pinned as per normal




Sankar WN et al. The modified Dunn procedure for unstable slipped capital femoral epiphysis: a multicentre prospective.

JBJS (Am). 2013; 95:585- 91.

- 26% Rate of AVN

- 15% Revision of metalwork rates

- therefore capable of restoring anatomy but ongoing risk of AVN and metalwork complications.


Prophylactic Pinning




Can justify but may cause complications 

- i.e. chondrolysis, subtrochanteric fracture secondary to screw


Incidence bilateral slips

- unknown

- may be > 35%

- high incidence of asymptomatic and mild contralateral slips


Major indications

- young i.e < 10 years

- unreliable parents

- geographic isolation

- Secondary SUFE eg endocrinopathy


Technique of Pin in Situ


Set up


1.  Supine on radiolucent table

- very easy to set up

- much faster if pinning both sides / reduced set up

- theoretical risk of displacing slip / inadvertant manipulation

- lateral by flexing and full ER of hip / frog legs


2.  Traction Table

- easy to get AP and lateral

- need 2 set ups for bilateral pinning

- takes longer in this regard




Draw anterior and lateral lines

- get AP, draw line mark using radiopague ruler to centre of head

- get lateral, repeat

- intersection of points is incision site


Stab incision

- guide wire percutaneously to neck

- more anterior entry point on femoral neck required the more the epiphysis is displaced posteriorly

- more anterior entry point ensures less likely to start at a subtrochanteric position and risk stress fracture

- central in head on both views

- ensure don't penetrate head

- cannulated drill

- 6.5/ 7.0/ 7.3 screws

- 8-10 mm or 4-5 threads across physis

- do far and away screening / approach withdraw; circumferential screening

- this ensures screw is not in joint